Thomas Blazek

SAL Silicon Austria Labs · Wireless Communications

This paper proposes and discusses the architecture for a real-time vehicular channel emulator capable of reproducing the input/output behavior of nonstationary time-variant radio propagation channels in safety-relevant vehicular scenarios. The vehicular channel emulator architecture aims at a hardware implementation which requires minimal hardware...

Accurate predictions of vehicular communication conditions are vital for the development of intelligent transport systems and services, both on link level through channel models, as well as packet error models on system level. In this paper we investigate simple, yet flexible tapped delay line channel models that capture the essential aspects of ve...

We propose a general framework for the specification of a sparse representation of millimeter wave vehicular propagation channels and apply this to both synthetic data and real-world observations from channel sounding experiments. The proposed framework is based on the c-LASSO (complex Least Absolute Shrinkage and Selection Operator) which minimize...

Vehicles are increasingly becoming connected and short-range wireless communications promise to introduce a radical change in the drivers' behaviors. Among the main use cases, the intersection management is surely one of those that could mostly impact on both traffic safety and efficiency. In this work, we consider an intersection collision warning...

Bluetooth Low Energy (BLE) is one of the key enablers for low-power and low-cost applications in consumer electronics and the Internet of Things. The latest features such as audio and direction finding will introduce more and more devices that rely on BLE for communication. However, like many other wireless standards, BLE relies on the unlicensed 2...

Nowadays Internet-of-Things and Industry 4.0 devices are often connected wirelessly. Current wireless sensor network (WSN) deployments are relying in most cases on the industrial, scientific and medical (ISM) bands without centralized resource scheduling. Thus, each device is a potential source of interference to other devices, both within its own...

Vehicular communications face unique security issues in wireless communications. While new vehicles are equipped with a large set of communication technologies, product life cycles are long and software updates are not widespread. The result is a host of outdated and unpatched technologies being used on the street. This has especially severe securi...

This paper describes the measurement setup for the proliferation of the vehicular communication systems in operating cars. The setup builds on a communication sniffer which detects cooperative awareness messages broadcast from ETSI ITS-G5 systems, decodes them and records the public information in these messages. The experimental characterization o...

Functional safety has become a crucial part of industrial automation. With industry environments being connected more than ever, achieving required functional safety depends on establishing safety-critical communication. Numerous application layer safety protocols have been developed to ensure compliance with functional safety standards for wired c...

Industrial wireless sensor networks are becoming crucial for modern manufacturing. If the sensors in those networks are mobile, the position information, besides the sensor data itself, can be of high relevance. E.g. this position information can increase the trustability of a wireless sensor measurement by assuring that the sensor is not physicall...

For Cyper-Physical Production Systems (CPPS), localization is becoming increasingly important as wireless and mobile devices are considered an integral part. While localizing targets in a wireless communication system based on the Received Signal Strength Indicators (RSSIs) is a usual solution, it is limited by sensor quality. We consider the scena...

Propagation graphs (PGs) serve as a frequency-selective, spatially consistent channel model suitable for fast channel simulations in a scattering environment. So far, however, the parametrization of the model, and its consequences, have received little attention. In this contribution, we propose a new parametrization for PGs that adheres to the dou...

The proliferation of embedded systems, wireless technologies, and Internet protocols have made it possible for the Internet-of-things (IoT) to bridge the gap between the physical and the virtual world and thereby enabling monitoring and control of the physical environment by data processing systems. IoT refers to the inter-networking of everyday ob...

The performance of a multiuser multiple-input multiple-output (MIMO) system is mainly determined by the correlation of user channels. Applying channel models without spatial correlation or spatially inconsistent channel models for performance analysis leads to an underestimation of spatial correlation and therefore to overly optimistic system perfo...

This paper presents an analysis of the Orthogonal Time Frequency Space (OTFS) modulation scheme when applied to realistic vehicular channel situations. OTFS modulates symbols in delay-Doppler domain, hoping to exploit diversity in both. The penalty for doing this is the requirement of complex interference cancellation equalizers, as this domain inc...

In this work, we show the design and validation of a testbed for over-the-air testing of millimetre waves equipments. We have extended the frequency capabilities of a baseband channel emulator which is capable of emulating non-stationary channels, to higher frequencies. To assure that the propagation between devices-under-test and the RF-frontend o...

Vehicular communications promise to be an essential driver for roadside safety in the future, as well as an important building block of autonomous driving. Communication standards that consider this communication mode specifically have been published as early as 2007 and continue to be refined. However, the nature of this application makes it espec...

All too often, the performance of vehicular communications is benchmarked merely for a single link. A major challenge for benchmarking the performance of multiple interacting vehicles is the definition of repeatable vehicular scenarios. In this study, the authors propose and discuss an approach for performance analysis of the IEEE 802.11p standard...

In the area of research on massive multiple-input multiple-output (MIMO), two assumptions on the wireless channel dominate channel modeling. Either, a rich scattering environment is assumed and the channel is modeled as i.i.d. Rayleigh fading, or, a line of sight (LOS) channel is assumed, enabling geometric channel modeling under a farfield assumpt...

Orthogonal time-frequency space (OTFS) modulation has been suggested as modulation scheme for the fifth generation of wireless communications and beyond. The scheme is promoted as especially well apt to tackle future challenges of high mobility, millimeter wave communications (mmWave) and massive Multiple-Input Multiple-Output (MIMO). In this paper...

Network level modeling of vehicular networks usually takes one of two paths. Either a mobility simulator is used to generate vehicular movement traces, combined with a network simulator to simulate packet transmissions. Or, simple stochastic assumptions, such as Poisson Point Processes and Manhattan Grids are imposed to allow analytical modeling. I...

For analysis of vehicle-to-vehicle (V2V) communications , a firm understanding of the underlying channel is crucial. Through spatial filtering of narrow beams millimeter wave (mmWave) channels become sparse. As accurate channel models are required, without overfitting channel measurements, we investigate the optimal model order given V2V mmWave cha...

Understanding millimeter wave (mmWave) vehicular channels is crucial for the application of mmWave technologies in vehicle-to-anything settings. However, as of yet, few attempts of low-complexity approximation of such channels exist. Prior results have shown that such channels are often composed of clustered multipath components, and this work buil...

Network simulators are a crucial tool for evaluat- ing the performance of Vehicular Ad-Hoc Network (VANET) protocols. They allow the assessment of the scalability and the influence of geometric topologies. However, typical network simulators such as NS-3 or OMNET++ often resort to overly simplified packet error models, limiting the validity of the...

The performance of vehicular communication standards is usually evaluated using simulations, or, if measurements are conducted, they are conducted on single links. This is due to the difficulty of having a controlled vehicular environment with multiple nodes interacting. In this paper, we present our approach on performance analysis of the IEEE 802...

Safety applications for cooperative intelligent transport systems are limited in their performance by the latency of the communication more than by the achieved throughput. However, there exist few models at packet level that are able to capture the burstiness of the communication. We~therefore introduce a packet error model that considers burst le...

Vehicle-to-Vehicle channels pose large modeling challenges due to their time-varying nature and their large Doppler shifts. While new descriptions for the channel are being researched, many standardization bodies and hardware manufacturers still rely on the concept of a tapped delay line as channel description. In this paper, we rephrase the proble...

Accurate simulations of Vehicle-to-Any communication networks at urban intersections need to be based on precise models. We approach this by analyzing the distribution of neighboring vehicles a communication node sees as a function of the distance to the closest intersection. Our analysis is based on real world map data from the city of Linz in Aus...

System-level simulations have become an indispensable tool for predicting the behavior of wireless cellular systems. As exact link-level modeling is unfeasible due to its huge complexity, mathematical abstraction is required to obtain equivalent results by less complexity. A particular problem in such approaches is the modeling of multiple coherent...